Hi, I am using the AD7730 and i have some problems with the Internal zero-scale calibration. I use the SPI interface to communicate between my uC and the AD converter.
I am able to wirte and read from the registers of the AD7730.
The converter is configured in bipolare mode, HIREF = 1( 5V ), Range : +-10mV, 16bit mode.
I am using two AD7730 parallel which are selected with two CHIP-Select.
After a calibration cycle the value of the corresponding Offset-Register changed by a very small value but there is still an offset(approx. 30150) to the expected value of 32768 when the input pins are shorted.
Has anyone any advices?